package com.xd.clap.utils;

import lombok.extern.slf4j.Slf4j;
import org.springframework.web.multipart.MultipartFile;
import sun.misc.BASE64Decoder;

import java.io.*;
import java.nio.file.Files;

/**
 * base64转MultipartFile
 */
@Slf4j
public class BASE64ToMultipartFile implements MultipartFile {


    private final byte[] imgContent;
    private final String header;

    public BASE64ToMultipartFile(byte[] imgContent, String header) {
        this.imgContent = imgContent;
        this.header = header.split(";")[0];
    }

    @Override
    public String getName() {
        return System.currentTimeMillis() + Math.random() + "." + header.split("/")[1];
    }

    @Override
    public String getOriginalFilename() {
        return System.currentTimeMillis() + (int) (Math.random() * 10000) + "." + header.split("/")[1];
    }

    @Override
    public String getContentType() {
        return header.split(":")[1];
    }

    @Override
    public boolean isEmpty() {
        return imgContent == null || imgContent.length == 0;
    }

    @Override
    public long getSize() {
        return imgContent.length;
    }

    @Override
    public byte[] getBytes() {
        return imgContent;
    }

    @Override
    public InputStream getInputStream() {
        return new ByteArrayInputStream(imgContent);
    }

    @Override
    public void transferTo(File dest) throws IOException, IllegalStateException {
        try (OutputStream fos = Files.newOutputStream(dest.toPath())) {
            fos.write(imgContent);
        }
    }

    public static MultipartFile base64ToMultipart(String base64) {
        try {
            String[] baseString = base64.split(",");
            BASE64Decoder decoder = new BASE64Decoder();
            byte[] b = decoder.decodeBuffer(baseString[1]);

            for (int i = 0; i < b.length; ++i) {
                if (b[i] < 0) {
                    b[i] += (byte) 256;
                }
            }
            return new BASE64ToMultipartFile(b, baseString[0]);
        } catch (IOException e) {
            log.error("error", e);
            return null;
        }
    }


}
